title: Metal-insulator transitions in the half-filled ionic Hubbard model.
abstract: We study electronic phase transitions in the half-filled ionic Hubbard model with an on-site Coulomb repulsion U and an ionic energy Δ by using the coherent potential approximation. For a fixed and finite Δ two transitions from the band insulator via a metallic state to a Mott insulator are found with increasing U. The values of the critical correlation-driven metal-insulator transitions U(c1)(Δ) and U(c2)(Δ) are estimated. Our results are in reasonable agreement with the ones obtained by single-site dynamical mean-field theory and determinant quantum Monte Carlo simulation.
authors.affiliation: Asia Pacific Center for Theoretical Physics, POSTECH, San 31 Hyoja-dong, Pohang 790-784, Korea. hatuan@iop.vast.ac.vn
authors.forename: A T
authors.initials: AT
authors.lastname: Hoang